<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .d1{
            width: 200px;
            height: 200px;
            background: red;

            /* border-top-left-radius: 20px;
            border-bottom-left-radius: 20px; */
            /* border-radius: 20px 40px 10px 50px; */
            /* border-radius: 20px; */
            /* border-radius: 20px 40px; */

            /* border-radius: 100px; */
            border-radius: 50%;
        }

        .d2{
            width: 100px;
            height: 200px;
            background: green;
            border-radius: 100px 0 0 100px;
        }
        .d3{
            width: 200px;
            height: 100px;
            background: blue;
            border-radius: 100px 100px 0 0;
        }
    </style>
</head>
<body>
    <div class="d1"></div>

    <div class="d2"></div>

    <div class="d3"></div>

</body>
</html>